>In the 1970s, Vera Rubin uncovered a discrepancy between observed galactic rotation speed and that predicted by the visible mass of stars and gas. Today, the galaxy rotation problem is thought to be explained by the presence of large quantities of unseen dark matter.
https://en.wikipedia.org/wiki/Galaxy#Modern_research
Is anti-matter the explanation for dark matter/energy, cosmological constant? Can anti-matter captured be anti-gravity?
>A significant discrepancy exists between the experimental curves observed, and a curve derived from theory. The theory of dark matter is currently postulated to account for the variance.
https://en.wikipedia.org/wiki/Galaxy_rotation_curve
>Galaxy clusters are the lights that trace out the contours of cosmic structure. But they’re only the tip of the proverbial iceberg: dark matter forms the cosmic web’s skeleton. Clusters sit in big halos of dark matter, and the more massive the cluster, the more dark matter is there. We know there’s something like ten times more matter than what we see in these clusters because, if there weren’t, the galaxies zooming around a cluster would be able to escape — the cluster would fly apart.
https://www.skyandtelescope.com/astronomy-news/dark-matter-makes-galaxy-clusters-clump-0502201623/